Abstract:
Limited research exists on full-shift and multi-day progression of fatigue during overhead work. This study investigates these patterns with workers across five construction trades. Thirty-five participants were assessed during their full working shifts. A test battery measuring shoulder maximal voluntary force (MVF), electromyography (EMG) during a 15% MVF test contraction, and rates of perceived exertion (RPE) of the neck, shoulders, back and arms were collected at the beginning, middle and end of the work shift. We evaluated fatigue effects using generalized linear mixed-effects models. Significant shift effects were observed for RPE, EMG amplitude and power frequencies (EMG_PF) and day effects for EMG_PF. We observed progressive onset of shoulder fatigue over a work shift and two consecutive working days. Although a test battery of EMG and MVF revealed both within- and between-shift fatigue effects, future research will investigate dose-response relationships between overhead exposures and shoulder fatigue.